Collaborating programs are grouped within task-specific virtual
machines (VMs) to scope their interactions. Conversations between
programs are multi-party (using a publish/subscribe medium), and
programs can easily participate in many such conversations at once.

Marketplace makes presence notifications an integral part of
pub/sub. Programs react to presence and absence notifications that
report the comings and goings of their peers. Presence serves to
communicate changes in demand for and supply of services, both within
a VM and across nested VM layers. Programs can give up
responsibility for maintaining presence information and for scoping
group communications to their containing VM.

Compiling and running the code

from the root directory of the Git checkout to install the package
from a local snapshot. (Alternatively, make link does the same thing.)
This will make #lang marketplace available to programs.

At this point, you may load and run any of the example *.rkt files
in the
examples/
directory.

Note that both the echo server and chat server examples do not print
any output on standard output: instead, they simply start running and
silently await TCP connections. Once one of the servers is running, in
a separate window, try telnet localhost 5999.

Note also that both the echo server and the chat server use port 5999,
so you cannot run both simultaneously.